Relationship Help(PLEASE)

The day after my friends were really sad. Sadder than me. Me and my ex have the same math class. We were working on a group project and he was being really slow. I was trying to rush him and he said "and I was the one told not to be an asshole" even though I'm always like that. 

After school I was invited to a group chat on instagram that someone named "fuck boy" because my ex was in it and saying that he was texting three of his exes like he was proud of it. He also said that he blocked me. My girl friend told me he invited me to the chat. I got really pissed and left the chat. 

The next morning, which is today, he sent me this really long text message saying how sorry he was and that he was an idiot for ruining HIS happiness. I deleted the text. At school, some of my friends and his said that we should get back together, that we were "meant for each other". We're only in eighth grade so this really bothered me. They couldn't understand why I didn't care. Some things he did really bothered me, so I felt kind of relieved when we broke up. I just didn't understand why he was being such an ass. After school today,he texted me "can we talk so at least we're on good terms" and "why are you pissed at me". I ignored him.

What should I do?

Sorry for ranting, I'm surprised if you read all that.